Straight beam clamp with an adjustable self-locking jaw



Feb. 2, 1960 c. M. BRENNAN, JR 2,923,334

STRAIGHT BEAM CLAMP WITH AN ADJUSTABLE SELF-LOCKING JAW Filed June 17, 1958 INVENT OR Charles M. Brennan JK United States atent STRAIGHT BEAM CLAlVIP WITH AN ADJUSTABLE SELF-LOCKING JAW Charles M. Brennan, Jr., New Haven, Conn. Application June 17, 1958, Serial No. 742,642 1 Claim. (Cl. 144-303) This invention relates to clamps, and relates more particularly to a clamp of the type which may be employed to clamp together a plurality of pieces of Wood, for example, after glue has been applied to them, to hold them together until the glue has set.

One object of the invention is to provide an improved clamp of the type characterized above. Another object is to provide in a clamp such as characterized above, an improved adjustable jaw of the self-locking type. Further objects of the invention will be apparent from the following detailed description of the clamp shown in the accompanying drawing.

In the drawing:

Fig. 1 is a fragmentary elevational view illustrating a clamp embodying the invention and showing the jaws of the clamp in position to clamp together a number of pieces of wood;

Fig. 2 is a fragmentary top plan view-of the clamp;

Fig. 3 is an enlarged sectional view taken on line 3-3 of Fig. 2 and further illustrating the self-locking jaw of the clamp in the locked position thereof;

Fig. 4 is a similar view but illustrates another position of the jaw; and

Fig. 5 is a sectional view taken on line 5-5 of Fig. 1.

In the drawing, the clamping bar or rod of the clamp, is indicated at and may be formed of a section of iron pipe having a threaded end 11. The threaded part of the bar is received in an internally threaded sleeve member 12 to be held fast by the latter. The member 12 has an integral laterally projecting extension 13 having a threaded bore therethrough to serve as a fixed nut and receive a screw 14 arranged lengthwise of the bar 10 to impart movement to a jaw 17 slidable on the bar, the bar and the screw being spaced apart in the manner shown in Fig. 1. The outer end of the screw 14 beyond the member 12 is provided with a manually operable operating member 15 secured thereto as by a pin 16. The operating member 15 is elongated transversely of the screw 14 and is secured to the latter intermediate the ends of the member 15. When the operating member is rotated by the user to effect movement of the jaw 17 along the bar 10, the thumb of the users right hand, for example, may press against the blade-like portion 18 of the member may be held in the palm of the same hand.

As shown in Fig. 1, the movable jaw 17, which is bolted, as at 20, to the end of the screw remote from the operating member 15, is of a height approximating the member 12 and its vertical extension 13 and has a flat work-pressing face, as at 21. The jaw 17, which is of the form shown in Figs. 1 and 2, is provided with a suitable opening through which the bar 10 is extended, the arrangement being such that the jaw 17 is supported by the bar for movement along the latter.

The other jaw of the clamp is indicated at 22 and this jaw is of substantially the same vertical dimension as the jaw 17 and is provided with a flat work-pressing face 23, which, in the position of the jaw shown in Fig. 1, is in 15 while the knob 19 of the member 15 2,923,334 Patented Feb. 2, 1960 tubular part 25.

As shown in'Figs. 3 and 4, the internal diameter of the tubular part 25 is, throughout the greater part of its length, considerably in excess of the outer diameter of the bar 10, but adjacent the inner end thereof is provided with any annular restriction of'knife-like form, which,

when the jaw 22 is in the position of Fig. 3, tends to bite into the bar to prevent dislocation of the jaw in a direction away from the jaw 17. The knife-like restriction, indicated at 27, is inclined with respect to the flat face 23 of the jaw. It has been found that an inclination of the biting edge 27 of approximately 15 from the vertical is critical for the achievement of best results. The jaw 22 is formed of a metal of great hardness to facilitate the biting or binding of the knife-like edge 27 with the bar when the jaw 22 is in the clamping position shown in Fig. 3.

However, when there is no work pressing the jaw 22, the jaw 22 may be tipped to the position of Fig. 4 and moved freely along the bar 10 so that it may be properly positioned in accordance with the width of the particular work which it is desired to clamp. It may be noted that the internal diameter of the annular knife edge 27 is only slightly in excess of the external diameter of the bar 10. In connection with the form of the knife-like edge 27 it may be noted that above the bar the knife-like edge 27 is formed in part by a gently tapered portion 28 of the jaw 22. Below the part 10 the jaw is sharply tapered, as at 28 and even more sharply tapered, as at 29. The inner portion of the tubular part 25 of the jaw is very sharply tapered above the bar, as at 30. The abovementioned tapers provide the knife-like edge 27 which is quite sharp, especially at the lower part thereof. It will be noted that the upper part of the edge 27 is provided with its more sharply tapered portion, the portion 30, facing away from the work. This facilitates greater binding of the edge 27 to resist movement of the jaw away from the work when the jaw is in the workclamping position.

In view of the foregoing disclosure, it is believed that the operation of the clamp will be manifest. To clamp two or more pieces of Wood together, the movable jaw 22 is tipped to the extent indicated in Fig. 4 and moved along the bar to the desired position so that the work may be interposed between the two jaws of the clamp. Then the manually operated member 15 is rotated to effect movement of the screw in a direction to press the jaw 17 against the work and to press the work against the jaw 22. Pressure of the work on the jaw 22 effects movement of the latter from the tipped position of Fig. 4 to the upright position of Fig. 3. When the jaw 22 is in the upright position shown in the last-mentioned view, it binds very strongly against the bar and thereby resists outward movement along the bar. To release the work from the clamp the operating member 15 is rotated in the other direction and this backs off the jaw 17 so that the work may be easily slipped out of the clamp.

In accordance with the foregoing disclosure, there is illustrated an improved clamp which is constructed of few and rugged parts and is economical to produce while being very efiicient and reliable in operation. There is also provided a clamp having a self-locking jaw of im proved construction.

While only one form of the clamp has been illustrated in the drawing and described above, it will be apparent to those versed in the art that the clamp is susceptible of various changes and modifications in details without departure from the principles of the invention and the scope of the appended claim.

What I claim is:

A: clamp comprising a cylindrical supporting. bar, means fixed to one end of the bar for supportinga handle. equipped screw, a handle-equipped screw threaded] through said means in parallel relation to the barrier. lengthwise movement of the screw, a first or. self locki'ng" eter considerably larger than the diameter of the bar,v the first jaw having at the inner end of the cylindrical part a flange extending above and below the bar. and providing,

a fiat work-engaging face which in the clamping position of the jaw is in a plane normalto the bar, the first jaw also having an annular knife-like restriction adjacent the inner end of the cylindrical part and. inclined downwardl-,. ly and inwardly at an angle offapproximatel'y 15 to a; plane, normal to the bar when the jaw is in clamping.

position, said knife-like restriction being deeper overth bar than under it and tending to bite into said bar and resist dislocation in a direction away from the work when the work is pressed against the first jaw, the portion of the knife-like restriction which lies below the bar being formed by sharply tapered inner and outer surfaces, and the portion of the knife-like restriction which lies above the bar being formed by a gently tapered inner surface and a sharply-tapered outer surface, the firstjaw when not pressed by the work being tiltable inwardly on the bar to a limited extent and being adjustable along the bar when in tilted position.

References Cited in the filev of this patent UNITED STATES PATENTS 1,371,080 Dupuy Mar. 8, 1921 1,806,527 Eisemann May 19, 1931 2,221,325 Holman- Nov; '12, 1940 2,262,429 Dicker" n Nov. 11, 1941" FOREIGN PATENTS. 17,419 Great Britain Ju1yr 26,. 19121 

